VELUX BFX 1000 Underfelt Collar and Transverse Drainage Gutter
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VELUX BFX 1000 Underfelt Collar and Transverse Drainage Gutter

Product Code: ky39293
(£19.91 ex VAT)

Delivery Info

3 - 5 day delivery


£36.00 fixed delivery fee
Size (W x H):
Call us for volume discounts – we won’t be beaten on price!
VELUX Underfelt Collar and Transverse Drainage Gutter.

The BFX Underfelt Collar ensures a fast connection between the VELUXRoof Window and the roofing felt/membrane. It helps to protect againstdrafts and wind driven rain and snow around the window installation.

It comes as one piece making fitting easy, especially around the window corners.

The tranverse drainage gutter included also prevents anywater ingress around the roof opening caused by missing or broken slatesor tiles above the window.

Product features

  • Can be used in all roofing constructions in roof pitches between 15º and 90º.
  • Is well suited for roofs with or without battens.
  • Can be used for both ventilated and unventilated constructions.
  • The underfelt collar is pleated and can be easily dressed round the battens of the roof, irrespective of the batten distance.


  • Special diffusion open underfelt of polypropylene and galvansied steel drainage gutter.

To view the full range of VELUX Products available, click here.

Q: Does this product include the insulation collar?

A: No, the Velux BFX 1000 kit includes only the underfelt collar and drainage gutter. 

You can, however, purchase the BFX together with the insulation collar in one kit:

Q: Is this a required product or can I get away with not having it?

A: The underfelt collar or the insulation collar (see question above) are not fundamentally necessary for the installation of your roof window -- in other words, you can fit your window without this product. However, Velux highly recommend the use of these installation accessories as they provide a higher spec, more weathertight, energy efficient seal, and you are less likely to have problems with your roof window in the long run if you use them.

3 – 5 day delivery. In most cases, products will be delivered within 3 – 5 working days. If you would like specific details on your product, please call 0844 488 0993 or email Ken’s Yard Customer Service

All deliveries require a signature – don’t get carded, let us know if your order can be left at a secure location. Job Done.

Returns Policy – Not happy with your order? We’ll let you return your order for a full refund, no reason required, provided the goods are with the original packaging and are returned within the time stated in an unused condition. Click on the link to view the full details

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